1. Field of the Disclosure
The present disclosure is in the field of methyl perfluoroheptene ether compositions. These compositions are azeotropic or azeotrope-like and are useful in cleaning applications as a defluxing agent and for removing oils or residues from a surface.
2. Description of the Related Art
Flux residues are always present on microelectronics components assembled using rosin flux. As modern electronic circuit boards evolve toward increased circuit and component densities, thorough board cleaning after soldering becomes a critical processing step. After soldering, the flux-residues are often removed with an organic solvent. De-fluxing solvents should be non-flammable, have low toxicity and have high solvency power, so that the flux and flux-residues can be removed without damaging the substrate being cleaned. For proper operation in use, microelectronic components must be cleaned of flux residues, oils and greases, and particulates that may contaminate the surfaces after completion of manufacture.
In cleaning apparatuses, including vapor degreasing and vapor defluxing equipment, compositions may be lost during operation through leaks in shaft seals, hose connections, soldered joints and broken lines. In addition, the working composition may be released to the atmosphere during maintenance procedures on equipment. If the composition is not a pure component, the composition may change when leaked or discharged to the atmosphere from the equipment, which may cause the composition remaining in the equipment to exhibit unacceptable performance. Accordingly, it is desirable to use a composition comprising a single unsaturated fluorinated ether as a cleaning composition.
Alternative, non-ozone depleting solvents have become available since the elimination of nearly all previous chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) as a result of the Montreal Protocol. While boiling point, flammability and solvent power characteristics can often be adjusted by preparing solvent mixtures, these mixtures are often unsatisfactory because they fractionate to an undesirable degree during use. Such solvent mixtures also fractionate during solvent distillation, which makes it virtually impossible to recover a solvent mixture of the original composition.
Many industries use aqueous compositions for the surface treatment of metals, ceramics, glasses, and plastics. Cleaning, plating, and deposition of coatings are often carried out in aqueous media and are usually followed by a step in which residual water is removed. Hot air drying, centrifugal drying, and solvent-based water displacement are methods used to remove such residual water.
While hydrofluorocarbons (HFCs) have been proposed as replacements for the previously used CFC solvents in drying or dewatering applications, many HFCs have limited solvency for water. The use of surfactant, which assists in removal of water from substrates, is therefore necessary in many drying or dewatering methods. Hydrophobic surfactants have been added to dewatering or drying solvents to displace water from substrates.
The primary function of the dewatering or drying solvent (unsaturated fluorinated ether solvent) in a dewatering or drying composition is to reduce the amount of water on the surface of a substrate being dried. The primary function of the surfactant is to displace any remaining water from the surface of the substrate. When the unsaturated fluorinated ether solvent and surfactant are combined, a highly effective displacement drying composition is attained.
Azeotropic solvent mixtures may possess the properties needed for de-fluxing, de-greasing applications and other cleaning agent needs. Azeotropic mixtures exhibit either a maximum or a minimum boiling point and do not fractionate on boiling. The inherent invariance of composition under boiling conditions insures that the ratios of the individual components of the mixture will not change during use and that solvency properties will remain constant as well.
The present disclosure provides azeotropic and azeotrope-like compositions useful in semiconductor chip and circuit board cleaning, defluxing, and degreasing processes. The present compositions are non-flammable, and as they do not fractionate, will not produce flammable compositions during use. Additionally, the used azeotropic solvent mixtures may be re-distilled and re-used without composition change.